Nitritation of anaerobic digestion centrate reduces aeration energy demand by preventing oxidation to nitrate and can be affected by changes in upstream processing of anaerobic digestate. Here we report autotrophic/heterotrophic nitritation and partial denitrification in a pilot-scale reactor treating anaerobic digester centrate amended with nitrogen-containing coagulants. The pilot reactor selected for a stable microbial community with nitritation of 60–65% of influent TKN; ∼30–35% nitrogen removal; low nitrate concentrations; and concurrent appearance of autotrophic and heterotrophic ammonia oxidizing bacteria (AOB). Dominant autotrophic AOB were Nitrosomonadaceae. Heterotrophic AOB included Xanthomonadaceae and Chitinophagaceae. Denitrifying bacteria included Comamonadaceae and Actinomycetales. The effects of coagulant dosage on nitritation were studied in bench-scale sequencing batch bioreactors (SBRs), where unclassified AOB were identified that had amoA sequences clustering between the autotrophic and heterotrophic clades. Heterotrophic nitritation was stimulated by glucose addition, especially in SBR biomass adapted to continuous coagulant addition, with elevated levels of Xanthomonadaceae, Chitinophagaceae, and Rhodanobacteraceae. Further research is needed to understand the effects of coagulants on downstream nitrogen removal unit operations and implications for land-application of treated biosolids.

中文翻译：

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含氮混凝剂对厌氧消化池硝化/反硝化的影响

厌氧消化液的硝化可防止氧化成硝酸盐，从而降低了曝气能量需求，并且可受到厌氧消化液上游工艺变化的影响。在这里，我们报告了中试规模反应器中的自养/异养硝化作用和部分反硝化作用，该反应器处理的厌氧消化池浓缩液经含氮混凝剂修正。选择的中试反应器用于稳定的微生物群落，其中硝化量为进水TKN的60–65％；约30–35％的脱氮率；硝酸盐浓度低；并同时出现自养和异养氨氧化细菌（AOB）。优势自养AOB为亚硝菌科。异养AOB包括黄单胞菌科和几丁菌科。反硝化细菌包括昏迷科和放线菌。在台式规模化分批生物反应器（SBR）中研究了混凝剂剂量对硝化的影响，在该反应器中，未分类的AOB被鉴定为具有在自养和异养进化枝之间聚集的amoA序列。葡萄糖的添加会刺激异养亚硝化，尤其是在适于连续添加凝血的SBR生物质中，黄原花科，壳多糖和罗丹杆菌科的水平升高。需要进行进一步的研究，以了解混凝剂对下游脱氮装置运行的影响以及对处理过的生物固体土地应用的影响。